Method and apparatus for use in surveying earth formation by explosion and seismograph



Sept. 13, 1955 c. E. BANNISTER 2,717,656

METHOD AND APPARATUS FOR USE IN SURVEYING EARTH FORMATION BY EXPLOSION AND SEISMOGRAPH Filed Oct. 31, 1951 IN VEN TOR. CLYDE E. BANNISTER ATTORNEY United States Patent F METHOD AND APPARATUS FOR USE IN SURVEY- ING EARTH FORMATION BY EXPLOSION AND SEISMOGRAPH Clyde E. Bannister, Houston, Tex.

Application October 31, 1951, Serial No. 254,108

7 Claims. (Cl. 181-05) This invention relates to procedure and apparatus for accurately placing a charge of an explosive and setting it 011 at an accurately predetermined time, to set up a pattern of earth shocks, to be recorded by seismograph, in the surveying of earth formation, as in exploration for petroleum.

Up until now, so far as I am aware, the common practice has been to drill a hole in the ground, usually to a depth of about 30 feet, for the placing of the powder therein, or a charge of the explosive has been mounted upon a pole a little distance, usually about 10 feet, above the ground.

In either case, this involves transporting of drilling equipment to the site and carrying on of the work wholly as a surface operation, which is a matter of considerable time and expense, especially when the site is in marshy or densely wooded ground, or at a great distance from the base of operation, or in ground either shallowly or deeply covered by water.

My chief objects are to effect economy of time, man power and equipment.

Of the accompanying drawings:

Fig. 1 is a perspective view, from below, of apparatus embodying and adapted for the practice of my invention in its preferred form.

Fig. 2 is a vertical section of a surface layer of the earth with a part of my apparatus therein as adapted for an underground shot.

Fig. 3 is a similar section but illustrating an aboveground shot.

In the practice of my invention an aerial vehicle, preferably a helicopter 10, because of its hovering and altitude-controlling ability, is used for transporting to position over and a determinate distance above the site of the desired blast, an explosive-carrying and firing, earth-penetrating tool 11.

The powder charge is placed in readiness for being exploded, by dropping the tool from a suitable height, or letting it descend by gravity at a suitable speed, to cause the tool to penetrate the ground to a suitable depth.

Preferably the tool is connected by a cable 12 with quick let-off means such as a bracket and pulley on the helicopter. The tool is in the form of an elongated shaft, which can be a length of metal pipe 13, closed at its lower end by a screwed-on, pointed, penetrating-head 14. A chamber for powder 15 is defined by the head 14, the

lower part of the pipe wall, and a partition 16 fitted in the pipe and preferably welded in place so that it will not be blown out as a projectile.

For setting off the powder, means such as a blasting cap 17 can be mounted in a seat in the partition 16, extending into the powder as shown. The cap is provided with a pair of detonating electric wires 18, 18, for the closing of the circuit either in the helicopter or at a suitable place on the ground by landed personnel. Also, or alternatively, the cap can be provided with a time fuse 19, to be lighted either while the tool is still at the helicopter or by landed personnel after the tool has been dropped.

2,717,656 Patented Sept 13, 1955 ICE The invention is-not wholly. limited to these particular elements for setting off the blast, but they permit delay of the blast if desiredor necessary, as for withdrawalofthe helicopter to a safer height or. off-side position after the powder charge hasbeen placed by the tools penetration of the ground.

For an underground blast of predetermined depth, as in Fig. 2, the landing velocity of the tool will be determined in relation to the character of the ground, by the height from which the tool is dropped, or by the speed allowed to the let-oif means, in case the cable connection is maintained for salvage of part of the tool after the blast.

The head 14 preferably has substantial weight, so that in the case of a free falling of the tool the relative lightness of the rear part of the tool, in relation to its air resistance, will assure vertical descent and vertical attitude of the tool, without the necessity of stabilizing fins or the like.

In the embodiment shown in Fig. 3, for setting ofi a charge about 10 feet above the ground, the tool can be relatively short, as shown, and is dropped from an appropriately less height, as it needs to penetrate the ground only to a depth sufiicient to keep the tool upright while the powder is exploded.

In this case the penetrating head 14a is of course without powder, the powder charge 15a being mounted in the upper part of the pipe 1111 between partition members 16a and 16b.

Variations are possible without sacrifice of all of the advantages set out in the above statement of objects and without departure from the scope of the invention as defined in the appended claims.

I claim:

1. Apparatus for placing and setting off a charge of explosive, said apparatus comprising an air-borne vehicle capable of hovering over a predetermined ground position, an elongated earth stabbing and explosive-placing tool, and means on said vehicle for supporting said tool upon and dropping it from said vehicle to said position in free downward flight through the air by gravity, said tool comprising an elongated shaft having earth-stabbing means on its forward end, having means for containing a charge of explosive, and having means for setting off said charge by remote control from said vehicle after it has been determinately positioned by penetration of the ground by the tool and stopping of the tool by resistance of the ground to further penetration by the tool.

2. Apparatus as defined in claim 1 in which the chargecontaining means is wholly within the vicinity of the forward end of the tool.

3. Apparatus as defined in claim 1 in which the chargecontaining means is remote from the forward end of the tool.

4. Apparatus as defined in claim 1 in which the elongated shaft is a length of metal pipe.

5. Apparatus as defined in claim 1 in which the elongated shaft is a length of metal pipe, and the earth-stabbing means is a tapered metal head mounted on the forward end of the shaft.

6. Apparatus as defined in claim 1 in which the elongated shaft is a length of metal pipe, and the earth-stabbing means is a tapered metal head mounted on the forward end of the shaft, and, as a closure for the end of the pipe, constitutes a wall of the charge-containing means.

7. The method of making a seismographic survey of earth formation which comprises mounting a charge of explosive in fixed relation to an earth-penetrating implement, dropping said implement from a position high above ground and thus causing it to be stopped and fixedly positioned by stabbing its forward end into the earth, effecting detonation of the explosive charge, and seismographically recording earth shock resulting therefrom.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Clary June 29, 1920 Hough Oct. 25, 1921 McCollum June 5, 1928 Dudley Jan. 16, 1934 Silverman May 13, 1941 Flude May 19, 1942 4 Vertzinsky June 26, 1945 Barber Jan. 13, 1948 Murphy June 7, 1949 Zuschlag Aug. 15, 1950 Poulter Mar. 13, 1951 Ewing Feb. 26, 1952 Poulter Oct. 28, 1952 

